Re: Natural keys vs Aritficial Keys
Date: Mon, 06 Jul 2009 12:21:16 -0500
> On Jul 3, 3:19 am, "Walter Mitty" <wami..._at_verizon.net> wrote:
>> "Roy Hann" <specia..._at_processed.almost.meat> wrote in message
>> > My point is that the rows are logically duplicate but they have been
>> > rendered spuriously distinct by tacking on a meaningless but unique
>> > attribute. So such an update is easy (perhaps inevitable).
>> This is an enormously important point, one that gets overlooked time and
>> time again in the discussion of databases.
> Oh, I think I understand the point now. Indentical duplicates are
> preferable to spuriously distinct rows.
Well, in the sense that identical duplicates can be detected and flagged, yes, a detectable problem is preferable to an undetectable one.
> With identical duplicates, you
> know you have duplicate data, and it stays that way.
Knowing you have duplicates is better than not even being able to tell you have duplicates, yes. And keeping them duplicate is better too, because once you mutate one or all of them, you then have ambiguities, with no logical basis to prefer one over any other. Then you really would be screwed!
> With spuriously
> distinct rows, you may not become aware of their spurious nature
> without non-trivial scrutiny.
-- RoyReceived on Mon Jul 06 2009 - 19:21:16 CEST